Production of terpene resins



United States Patent 3,415,798 PRODUCTION OF TERPENE RESINS Henry G.Sellers, Jr. and Henry E. McLaughlin, Pensacola, Fla., assignors toTenneco Chemicals, Inc., a corporation of Delaware No Drawing. Originalapplication Oct. 3, 1963, Ser. No. 313,416, now Patent No. 3,297,673.Divided and this application Nov. 1, 1966, Ser. No. 620,567

6 Claims. (Cl. 260-933) This application is a division of Ser. No.313,416, filed Oct. 3, 1963, now Patent No. 3,297,673.

This invention relates to improvements in the method of producingterpene resins in a high yield which are very light in color.

Various terpenes including beta-pinene, alpha-pinene, dipentene, and thelike having the empirical formula C H have been polymerized in a solventand in the presence of a metal halide catalyst of the Friedel-Craftstype, for example, AlBr BF ZrCl AlCl and the like. After polymerization,the polymer solution may be neutralized with calcium oxide or hydroxideand an adsorbent material, for example, finely divided clay may beadded. This mixture preferably is heated under reflux to decolorinatethe mixture and some of the solvent may be removed. Thereafter, themixture is filtered and the filtrate is distilled to remove the solvent.

It has been discovered that higher yields and lightercolored resins areobtained in a more readily controlled reaction by the use of acombination of solvents, each of which is a solvent for the terpenemonomer as Well as the terpene polymer. The combination of solventsincludes at least one aromatic solvent, for example, toluene, and atleast one aliphatic hydrocarbon solvent, for example, petroleum naphtha.Polymerization is effected in the solvent medium comprising toluene andnaphtha and thereafter, the toluene is removed prior to filtration ofthe adsorbent which contains the color bodies. Since toluene is asolvent for the catalyst complex and reduces the tendency of thecatalyst or catalyst complex to separate and collect on the walls of thereaction chamber, the heat of the exothermic reaction can be readilyremoved from the system in a controlled manner to avoid ex cessivelyhigh temperatures from develop-ing. The toluene is removed prior torecovery of the polymer as the toluene is a better solvent for the colorbodies than the naphtha and the presence of a substatnial amount of thetoluene inhibits separation of the color bodies by the adsorbentmaterial.

In a preferred procedure involving the polymerization of dipentene withaluminum chloride as a catalyst, a mixture of the catalyst and solventcontaining toluene and naphtha is prepared. Thereafter, the dipentene isgradually added to the agitated polymerization medium and the reactionmixture cooled, if necessary, to maintain the desired reactiontemperature. By this procedure the temperature during the polymerizationcan be better controlled,.particularly on large scale production, toavoid undesirably high temperatures which result in darker resins. Afterthe reaction is complete, the polymer solution is neutralized andpreferably heated under reflux to remove hydrochloric acid. Eitherduring the foregoing step or thereafter, substantially all of thetoluene is removed by distillation. Thereafter, a substantiallytoluenefree solution of the polymer is heated in the presence of andfiltered from an adsorbent material which aids in removing the colorbodies and other impurities. The catalyst may be removed by thefiltration step or it may be separated prior thereto, for example, bydecantation, or both. After filtration the solvent is separated from thepolymer, preferably by distillation and with the aid of a steam sparge.By this procedure dipentene resins of light color can be obtained inhigh yield.

While toluene has been found to be a highly satisfactory solvent, otheraromatic solvents which are a solvent for the monomer as well as thepolymer may be used. For example, benzene and xylenes may be used. Thearomatic hydrocarbon solvent should have a boiling point below theboiling point of the aliphatic hydrocarbon solvent so that the aromaticsolvent may be readily removed from the polymer solution prior toheating in the presence of and filtration from an adsorbent material. Ifa substantial amount of the aromatic solvent is present at the time offiltration, the resulting resin will have a darker color as this solventis a better solvent for the color bodies than naphtha and inhibits theirremoval by the adsorbent material.

Any aliphatic hydrocarbon solvent may be used which is a solvent for themonomer as well as the polymer and which has a boiling point above theboiling point of the aromatic solvent. The petroleum hydrocarbons, suchas kerosene, mineral spirits, and naphtha, may be used. Preferably thealiphatic hydrocarbon solvent has a boiling point below 200 C. tofacilitate its removal by distillation without overheating the polymer.Commercial grades of the two solvents may be used that have overlappingboiling point ranges as long as the aromatic solvent can be removed bydistillation leaving a major portion of the aliphatic solvent.

The total amount of solvent is the amount which will form solutionshaving the desired viscosity to facilitate handling and filtration.Normally the amount of solvent will vary from about 60% to by weight ofthe dipentene charged. Larger amounts of solvent may be used. However,this increases the cost of removing the solvent. An important advantageof toluene is that it permits the use of less total solvent. The minimumamount of toluene depends to a certain extent upon the amount ofcatalyst and the temperature of the polymerization reaction. Normallythe amount of toluene will vary from about 25% to 50% by Weight of theamount of dipentene. If the polymerization temperature is in the rangeof 4055 C., then the amount of toluene should constitute at least 20% byweight of the dipentene charged. At lower reaction temperatures somewhatmore toluene is required to dissolve the catalyst-dipentene complex. Forexample, at a reaction temperature of 30 C. a minimum of 30 pounds oftoluene per 100 pounds of dipentene is required. At a reactiontemperature of 20 C. a minimum of 40 pounds of toluene is required. Anexcess of toluene may be used. However, this increases the cost ofdistillation to remove the toluene prior to filtration with an adsorbentmaterial and, in general, an amount of toluene in the range of about 25to 50% by weight of the dipentene has been found to be highlysatisfactory. The remainder of the solvent system consists of thealiphatic hydrocarbon solvent.

In the following examples, all percentages are by weight.

EXAMPLE 1 The naphtha described in this example was petroleum naphthahaving a boiling point range of 118 C. to 148 C. Into a reactor therewas charged 4,300 pounds of naphtha and 7,100 pounds of toluene. Thesolvent was heated to remove any water which would tend to inactivatethe catalyst. Thereafter a slurry of 800 pounds of aluminum chloride in1,800 pounds of naphtha was added and the mixture agitated. Over aperiod of five hours 21,100 pounds of dipentene was gradually chargedwhile maintaining the reaction temperature in the range of 43 C. to 50C. It has been found that the reaction can be more readily controlled byadding the dipentene to the solvent and catalyst. The charge wasagitated for an additional 30 minutes at the same temperature tocomplete the reaction. A slurry of 800 pounds of calcium hydroxide in1,800 pounds of naphtha was added to the reaction mixture. A slurry of800 pounds of finely-divided clay and 1,800 pounds of naphtha also wasadded to the reactor. The temperature was gradually raised to 150 C.with reflux and 10,800 pounds of solvent was removed. The removedsolvent contained substantially all of the toluene and some of thenaphtha. The solution was then maintained under full reflux for fourhours to remove gaseous hydrochloric acid. The resulting reactionmixture was filtered hot.

The clarified solution of dipentene resin was heated and discharged intoa finishing still where most of the solvent was removed by flashdistillation. The pot temperature was gradually raised to 220 C. toremove the residual solvent and thereafter the material was sparged withsteam at the rate of 2,300 pounds per hour for 3 hours. During thesparging operation, some residual hydrochloric acid was removed as wellas some of the lower boiling components primarily consisting of dimersand trimers of dipentene. Thereafter, the resin was steamed at 220 C.until the desired melting point of the resin was obtained.

A typical resin prepared as described will have a Gardner color of about2 and a softening point of 110- 120 C. The Gardner color is determinedwith a 50% solution in mineral spirits and the softening point isdetermined by the ball and ring method. ASTM E28-58T. The softeningpoint can be varied depending upon the amount of low boiling componentswhich are removed.

EXAMPLE 2 The polymerization reaction was carried out in a flaskequipped with an agitator, a thermometer, and an addition funnel. Amixture comprising g. of aluminum chloride, 250 g. of toluene, and 250g. of naphtha (an aliphatic petroleum hydrocarbon fraction boiling inthe range of 118148 C.) was added to the flask and agitated. Fivehundred grams of dipentene was gradually added to the solution and thepolymerization reaction was easily initiated and was carried out at atemperature of 40 C. After the addition of the dipentene was complete,the mixture was allowed to stand for one hour and thereafter, g. ofcalcium hydroxide and 25 g. of acid-activated clay were added. The flaskwas equipped with a reflux condenser and a water trap. The mixture washeated with stirring and solvent removed through the trap until thetemperature in the flask reached 140 C. This removed all of the tolueneand a small amount of the naphtha. The mixture was refluxed overnightwithout the removal of any additional solvent. The resin solution wasseparated by filtration while hot. The clarified solution was thendistilled to a pot temperature of 2l0220 C. to remove the solvent andsparged with steam until 500 ml. of water was formed in the distillate.The resulting resin weighed 350 g., had a ball and ring softening pointof 113 C., and a 50% solution in mineral spirits had a Gardner color of1.

EXAMPLE 3 A polydipentene resin was produced in the same manner asdescribed in Example 2 except that no toluene was used. The flask wascharged with 500 g. of naphtha (B.P. 118148 C.) and 10 g. of aluminumchloride. Five hundred g. of dipentene was added gradually through thefunnel. Below 50 C. polymerization did not occur until a large excess ofdipentene had been added and then the polymerization reaction wasaccompanied by a sudden rise in temperature. As a result the reactionwas carried out at 5560 C. After the addition of dipentene was complete,the mixture was allowed to stand for one hour to complete the reaction.A reflux condenser was added to the flask in place of the additionfunnel after 25 g. of lime and 25 g. of acid activated clay had beenadded. The mixture was heated with Stirring and solvent was removeduntil the pot temperature reached 140 C. No more solvent was removed andthe mixture was refluxed overnight. Thereafter, the solution wasfiltered while hot and the filter cake was washed with naphtha. Theresin solution containing the wash naphtha was heated to a pottemperature of 210-220 C. with a steam sparge until 500 ml. of water wasformed in the distillate. The resinous product weighed 270 g., had asoftening point of 39 C., and a 50%. solution in mineral spirits had aGardner color of 6-5.

Without the toluene the yield was lower and the reaction was difficultto control. The sudden rise in temperature caused an increase in thecolor. In addition to the lower yield, it is to be noted that the resinproduced without toluene had a much lower softening point indicating thepresence of a relatively large amount of dimer and trimer. While thesoftening point of the resin could be increased by removing some ofthese low boiling components, this would further reduce the yield ofdesirable higher molecular weight polymer product.

The temperature at which polymerization is effected also influences theyield and the characteristics of the resinous product. Preferably, thepolymerization temperature of dipentene is in the range of 40-50" C.Lower temperatures may be used to produce excellent products in highyields; however, more time is required, and for practical reasons,temperatures below 30 C. are not used nor mally. The highertemperatures, and particular temperatures above 55 C., result inproducts having darker colors and lower melting points, the lastindicating a considerably lower degree of polymerization.

EXAMPLE 4 Three resins were prepared from the same quantities ofmaterials and under the same conditions except for variations in thepolymerization temperature.

In each instance 250 g. of toluene, 250 g. of naphtha, and 25 g. ofaluminum chloride were charged into a flask. Five hundred g. ofdipentene was then added gradually over a period of one hour, thetemperature being held constant by the application of a heating bathinitially and a cooling bath after the addition of dipentene wasstarted. After the addition of dipentene was complete, the temperaturewas maintained constant for an additional hour to assure completion ofthe reaction. Thereafter 25 g. of calcium hydroxide and 25 g. ofacid-activated clay were added. The flask was equipped with a water trapand a reflux condenser. The mixture in the flask was heated and agitatedand solvent removed through the water trap until the pot temperaturereached 140 C. No additional solvent was removed and the mixture Waspermitted to reflux overnight at 140 C. Hydrogen chloride vapors wereevolved during distillation and reflux.

The mixture was filtered hot and the resin solution was transferred todistillation apparatus equipped with a steam sparge. The pot temperaturewas gradually raised to 210-230 C. and steam sparged until 500 g. ofwater was condensed. The following table shows the effect of thevariations in the polymerization temperatures.

Polymerization Yield of resin Softening Gardner temperature (O.) byweight, point (0.) color percent oxidants may be added to the dipenteneto prevent the formation of the hydroperoxides during storage and thatthe antioxidant-containing dipentene may be readily polymerized. Theantioxidant does not interfere with the polymerization of the terpeneand in addition, the antioxidant is readily removed when the resinsolution is filtered with an adsorbent material. The presence of theantioxidant in the finished resin is undesirable especially when theresin is used in an adhesive or other manner in connection with foodpackaging. The phenolic antioxidant compounds are well known and includepolyphenols containing ortho and para-hydroxyl groups. Such antioxidantsare described in Encyclopedia of Chemical Technology, Raymond E. Kirkand Donald Othmer, vol. 2, p. 71, 1941. Representative phenolicantioxidants include hydroquinnone, pyrocatechol, pyrogallol, sesamol(3,4-methylenedioxyphenol), 3-phenylisocoumaraonone, a-naphthol, andalkylene bis phenols containing a hydroxyl group on each benzene ring inthe para position.

EXAMPLE 5 Two polydipentene resins were prepared in exactly the samemanner from two different batches of dipentene. The first batchcontained 0.88% terpene peroxides. The second batch of dipentenecontained 0.1% 4,4'-methylene bis (2,6-di-tert. butylphenol) as anantioxidant. In each instance 500 g. of the dipentene was graduallyadded to 250 g. toluene and 250 g. naphtha containing g. of aluminumchloride. The polymerization temperature was maintained at C. After theaddition of dipentene was a complete, the mixture was allowed to standfor one hour to complete the reaction. Thereafter, 25 g. of calciumhydroxide and 25 g. of acid-activated clay was added. The mixture washeated with stirring and solvent was removed until the pot temperaturereached 140 C. Thereafter, no more solvent was removed and the mixturewas refluxed overnight.

The resin solution was filtered while hot and transferred to a potequipped for distillation. The pot temperature was raised to 210-220 C.to remove most of the solvent and the contents sparged with steam until500ml. of Water had been collected in the distillate. The yield of eachresin was determined based on the dipentene charged. The softening pointof each resin was determined by the ball and ring method (as previouslydescribed) and the color of a solution of each resin in mineral spiritswas determined.

Dipentene Yield, Softening Gardner The resin produced from the dipentenecontaining the antioxidant was substantially free of antioxidant as aresult of the filtration with the adsorbent material. It is to be notedthat the presence of the peroxides not only reduced the yield andincreased the color but also resulted in the formation of a resin havinga much lower softening point as a result of the peroxides interferingwith the polymerization by deactivation of the catalyst. This effect ofthe peroxides has been found to be consistent.

The amount of antioxidant used depends to a certain extent upon storageconditions. However, in general, from 0.5% to 1% is sufiicient. Moreantioxidant may be used. However, it is usually unnecessary and, ofcourse, must be removed.

In all of the foregoing examples the acid-activated clay was clay whichhad been treated with acid to remove some of the aluminum and magnesiumions. It has been found that finely-divided clays may be used which havenot been acid-activated, for example, Fullers earth may be used.Preferably, the clay is in a finely-divided condition to provide arelatively large adsorbent area. While no particular degree of finenessis required, however, at least most of the particles preferably shouldpass a mesh screen. In general, from 1%l0% of finely-divided clay may beused. Smaller amounts tend not to be sufficiently effective and largeramounts are not normally required. Similarly, the amount of basicmaterial, such as calcium oxide or calcium hydroxide, may be within therange of from 1% to 10% by weight of the dipentene charged. The use oflime with finely-divided clay is described in US. Patent No. 2,555,221.

In the foregoing examples, the solution containing the polymerizeddipentene is heated to remove the toluene and to aid in dechlorinationof the mixture. In general, the solution can be heated to a temperaturein the range of 200 C. to effect dechlorination with the preferredtemperature being in the range of l15170 C. During this heating step orprior thereto the aromatic solvent is removed. While some of the naphthamay be removed, preferably, the final portion of this heating step iscarried under substantially full reflux so that naphtha will not have tobe added before filtration. If necessary, naphtha may be added to obtainthe desired viscosity for filtration.

We claim:

1. The process of producing polyterpene resins comprising the steps ofpolymerizing substantially peroxidefree terpene in a solvent medium inthe presence of a phenolic antioxidant and a metal halide polymerizationcatalyst, and thereafter recovering the polyterpene resin.

2. The process of producing polyterpene resins comprising the steps ofpolymerizing substantially peroxidefree terpene in a solvent medium inthe presence of a phenolic antioxidant and a metal halide catalyst,filtering the polyterpene resin solution in the presence of clay,whereby the clay adsorbs the antioxidant, and recovering the polyterpeneresin from the filtrate.

3. The process of producing polyterpene resins comprising the steps ofadding a phenolic antioxidant to terpene while substantially free ofperoxides, polymerizing the terpene in a solvent medium in the presenceof a metal halide polymerization catalyst, adding finely divided clay tothe polyterpene resin solution, filtering the solution to separate theclay and adsorbed antioxidant, and recovering the polyterpene resin fromthe filtrate.

4. The process of producing polydipentene resins comprising the steps ofpolymerizing substantially peroxidefree dipentene in a solvent medium inthe presence of a phenolic antioxidant and aluminum chloride catalyst,and thereafter recovering the polydipentene resin.

5. The process of producing polydipentene resins comprising the steps ofpolymerizing substantially peroxidefree dipentene in a solvent medium inthe presence of a phenolic antioxidant and aluminum chloride catalyst,filtering the polydipentene resin solution in the presence of clay,whereby the clay adsorbs the antioxidant, and recovering thepolydipentene resin from the filtrate.

6. The process of producing polydipentene resins comprising the steps ofadding a phenolic antioxidant to dipentene while substantially free ofhydroperoxides of dipentene, polymerizing the dipentene in a solventmedium in the presence of aluminum chloride polymerization catalyst,adding finely-divided clay to the polydipentene resin solution,filtering the solution to separate the clay and adsorbed antioxidant,and recovering the polydipentene resin from the filtrate.

US. Cl. X.R. 260-4595, 33.4

1. THE PRESENCE OF PRODUCING POLYTERPENE RESINS COMPRISING THE STEPS OFPOLYMERIZING SUBSTANTIALLY PEROXIDEFREE TERPENE IN A SOLVENT MEDIUM INTHE PRESENCE OF A PHENOLIC ANTIOXIDANT AND A METAL HALIDE POLYMERIZATIONCATALYST, AND THEREAFTER RECOVERING THE POLYTERPENE RESIN.